全文获取类型
收费全文 | 788篇 |
免费 | 67篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 11篇 |
妇产科学 | 4篇 |
基础医学 | 84篇 |
口腔科学 | 12篇 |
临床医学 | 65篇 |
内科学 | 165篇 |
皮肤病学 | 17篇 |
神经病学 | 56篇 |
特种医学 | 37篇 |
外科学 | 161篇 |
综合类 | 27篇 |
预防医学 | 46篇 |
眼科学 | 8篇 |
药学 | 44篇 |
中国医学 | 6篇 |
肿瘤学 | 113篇 |
出版年
2024年 | 2篇 |
2023年 | 21篇 |
2022年 | 45篇 |
2021年 | 46篇 |
2020年 | 24篇 |
2019年 | 28篇 |
2018年 | 22篇 |
2017年 | 34篇 |
2016年 | 34篇 |
2015年 | 29篇 |
2014年 | 22篇 |
2013年 | 33篇 |
2012年 | 42篇 |
2011年 | 45篇 |
2010年 | 27篇 |
2009年 | 22篇 |
2008年 | 43篇 |
2007年 | 33篇 |
2006年 | 42篇 |
2005年 | 37篇 |
2004年 | 30篇 |
2003年 | 36篇 |
2002年 | 26篇 |
2001年 | 17篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1972年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有859条查询结果,搜索用时 15 毫秒
51.
Tatsuki Yoshimatsu Daisuke Yoshida Hiroyuki Shimada Taiki Komatsu Atsushi Harada Takao Suzuki 《Geriatrics & Gerontology International》2013,13(2):351-357
Aim: Near‐infrared spectroscopy (NIRS) allows estimation of the percentage of body fat (%BF) regardless of the patient's posture; thus, it is useful for assessment of elderly patients with severe decline of basic activity who cannot hold a standing position. However, the accuracy by which the near‐infrared light emitted from NIRS reflects subcutaneous tissue is unknown. The aim of this study was to assess how correctly NIRS reflects the subcutaneous fat and muscle thickness derived from ultrasonography in community‐dwelling elderly. Methods: A total of 93 community‐dwelling older adults aged 65 years and older were enrolled in this study (mean 75.8 years, 6.7 SD). Participants were assessed according to optical density (OD) measurements by NIRS, subcutaneous fat and muscle thickness by ultrasonography, and muscle strength. Pearson's correlation coefficients were calculated for each sex. Stepwise multiple regression analysis was used to identify factors that contributed to OD for each sex. Results: OD measured at the forearm and thigh were significantly correlated with subcutaneous fat thickness. In stepwise multiple regression analyses, subcutaneous fat thickness was found to be a significant determinant of OD in men (forearm β = −0.37, P = 0.01; thigh β = −0.63, P < 0.001) and women (forearm β = −0.50, P < 0.001; thigh: β = −0.52, P < 0.001). Conclusions: These results suggest that NIRS can appropriately estimate fat‐free mass. By adding other variables to OD as the predictive variable, skeletal muscle mass might be estimated in the elderly population. Geriatr Gerontol Int 2013; 13: 351–357 . 相似文献
52.
53.
Sun DF Fujigaki Y Fujimoto T Goto T Yonemura K Hishida A 《American journal of nephrology》2002,22(5-6):405-416
AIMS: To elucidate the pathophysiological roles of the changes of distal nephron in uranyl acetate (UA)-induced acute renal failure (ARF), we investigated the relation of changes of constituent molecules in distal nephron to proximal tubular damage and repair in UA-treated rats. METHODS: ARF was induced in rats by intravenous injection of UA, and all rats received bromodeoxyuridine (BrdU) intraperitoneally 1 h before sacrifice. RESULTS: Proximal tubular damage with necrosis appeared as early as day 2, mainly in the outer stripe of outer medulla and reached a peak level at day 5. Slight cellular damage was evident in the distal nephron as early as day 3, reaching a peak level around day 9. Immunoreactive BrdU- or vimentin-positive regenerating proximal tubules (PT) appeared at day 2 and regenerating PT relining was almost completed by day 7. Immunostaining for EGF, which was constitutively expressed in the thick ascending limb (TAL) and distal convoluted tubule (DCT), diminished significantly as early as day 2, when PT regeneration became evident, and remained below normal levels until day 21. In contrast, slight immunoreactivity for EGF was observed in regenerated PT accompanying brush-border formation mainly after day 9, suggesting newly expressed EGF might contribute to PT maturation. Lectin staining or immunostaining for representative constituent molecules of the thin descending limb, TAL, DCT and collecting duct demonstrated marked and transient reduction after day 5. CONCLUSIONS: EGF was not associated with regenerating PT, but may be involved in the maturation of PT. Transient reduction in expression of constituent molecules of the distal nephron following the reduction in EGF could reflect dedifferentiation or phenotypic simplification during regenerative repair of PT in UA-induced ARF in rats. 相似文献
54.
Hoshikawa T Tanaka Y Kokubun S Lu WW Luk KD Leong JC 《Journal of spinal disorders & techniques》2002,15(2):139-143
A new concept, the motion axis of fracture (MAF), which is defined as the transitional point from anterior compressive to posterior splitting failure on a lateral radiograph, has provided a true understanding of the mechanisms of flexion-distraction injuries in clinical cases. This study was designed to produce in vitro injuries that have MAFs and to clarify the relation between the flexion angle and the MAF location. Adolescent porcine thoracolumbar spines were exposed to a vertical compressive load to failure at three different flexion angles and then examined radiographically. The MAF location was recorded as the distance from the anterior border to the MAF expressed as a percentage of the anteroposterior diameter of the vertebral body. All specimens showed similar injuries, with MAFs consisting of anterior compression fractures in the vertebral bodies and posterior disruptions. A significant negative correlation emerged between the flexion angle and the MAF location (r = -0.890; p < 0.0001). These results suggest that even a vertical compressive load contributes to the production of a flexion-distraction injury with an MAF in the thoracolumbar spine. They also indicate that the flexion angle of the spine at which the vertical compressive load is applied is an important factor in determining the MAF location; that is, the larger the flexion angle, the more anterior the MAF. 相似文献
55.
56.
Ossification of the Achilles tendon is a very unusual condition. We report a case with bilateral Achilles tendon ossification followed up for twelve years, treated twice surgically on the left side and conservatively on the right side. At the age of 51, the patient's plain radiogram showed bilateral ossifications of the Achilles tendon (right 55 mm, left 15 mm in length). The left side small mass was removed. The right side mass was decided to be followed up because of its large size. At the age of 61, ossification recurred on the left side. Conservative treatment with etidronate disodium for two years failed to prevent ossification from progressing. At the age of 63, the mass on the right and left sides increased to 70 mm and 45 mm in length, respectively. The mass of the left side was excised again, and dull pain disappeared postoperatively on the left side. 相似文献
57.
Irie T Aizawa T Kokubun S 《The Journal of bone and joint surgery. British volume》2005,87(9):1278-1284
Sex hormones play important roles in the regulation of the proliferation, maturation and death of chondrocytes in the epiphyseal growth plate. We have investigated the effects of male castration on the cell kinetics of chondrocytes as defined by the numbers of proliferating and dying cells. The growth plates of normal rabbits and animals castrated at eight weeks of age were obtained at 10, 15, 20 and 25 weeks of age. Our study suggested that castration led to an increase in apoptosis and a decrease in the proliferation of chondrocytes in the growth plate. In addition, the number of chondrocytes in the castrated rabbits was less than that of normal animals of the same age. 相似文献
58.
Hattori K Hatori M Hosaka M Watanabe M Smith RA Kokubun S 《Upsala journal of medical sciences》2005,110(2):173-178
This is a case report of a rare spindle cell lipoma (SCL) showing an unusual biphasic pattern with radiological findings and histological features. SCL is most common in men between the ages of 45 and 65 and it is reported that the tumor has a tendency to occur in the posterior neck area. This case was a 75-year old man with a 7 x 5 cm subcutaneous tumor in the posterior neck. Magnetic resonance imaging (MRI) examination demonstrated an unusual biphasic pattern. The signal intensities on T1 and T2 weighted images of the outer layer of the mass were high, and were suppressed on fat suppression views and showed no enhancement after gadolinium (Gd) injection. There was a low signal intensity area of 15 mm in diameter on both T1 and T2 weighted images, in the central part of the mass. This area was well enhanced with the Gd compound. Also macroscopically it could be seen that the excised tumor consisted of two different tissue components. Microscopically, the outer yellowish portion was mainly composed of mature adipose tissue. The inner whitish fibrous portion contained a mixture of small and uniform spindle-shaped cells, collagen fibers, and scattered mature adipose cells. No malignancy was observed. The diagnosis of spindle cell lipoma was made. No recurrence was seen seven months after marginal excision. 相似文献
59.
Two patients with spinal Langerhans cell granulomatosis were followed by magnetic resonance imaging, and the observed signal changes were detailed. Both patients had no neurologic abnormalities but back pain. They were treated by immobilization with a brace and bed rest. Their back pain disappeared after about a month. At the first visit, the tumorous lesions involving vertebrae showed mainly low signal intensity on T1-weighted imaging (T1WI) and high intensity on T2-weighted imaging (T2WI). They were clearly enhanced by gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). Their original intensities changed to iso-intensities on both T1WI and T2WI without enhancement by Gd-DTPA after a year. These signal changes might indicate the healing stage of the involved vertebrae and recommend the removal of the spinal brace. 相似文献
60.
Mizoue T Yamaji T Tabata S Yamaguchi K Shimizu E Mineshita M Ogawa S Kono S 《American journal of epidemiology》2005,161(4):338-345
The role of dietary patterns in colorectal carcinogenesis remains unclear in Asian populations. Using 1999-2002 data, the authors investigated the association between dietary patterns and colorectal adenomas in 1,341 Japanese men who underwent total colonoscopy. Information about diet was obtained using a 74-item food frequency questionnaire prior to the colonoscopy. Three dietary patterns were generated by factor analysis: 1) a high-dairy, high-fruit and -vegetable, high-starch, low-alcohol pattern; 2) an "animal food" pattern; and 3) a Japanese pattern. Logistic regression analysis was used to estimate the odds ratio of having colorectal adenomas with the adjustment for potential confounding variables including body mass index, smoking, alcohol, and leisure-time physical activities. A significant inverse association was found for the high-dairy, high-fruit and -vegetable, high-starch, low-alcohol pattern; the odds ratios for the second, third, and fourth quartiles were 0.97 (95% confidence interval: 0.70, 1.36), 0.71 (95% confidence interval: 0.50, 1.01), and 0.62 (95% confidence interval: 0.43, 0.90), respectively, compared with the lowest (p(trend) = 0.003). Similar associations were observed for larger adenomas or for each subsite of the colorectum. The Japanese and "animal food" patterns were not clearly associated with colorectal adenomas. A dietary pattern including greater consumption of dairy products and fruits and vegetables with low alcohol consumption may be associated with decreased risk of colorectal adenomas. 相似文献